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Biomedical subjects

A Marazzi

Publications and source records attributed to A Marazzi.

At least 19 recordsLinked to original sources
PubMed2001

Antioxidant liposoluble vitamins and carotenoids in chronic hepatitis.

Background: It is known that antioxidant liposoluble vitamins and carotenoids are reduced in liver cirrhosis, but little is known about chronic viral hepatitis, where oxidative damage has to be taken into account. Methods: Fifty-five patients with chronic hepatitis, mainly C virus-related, were matched with 16 patients with biliary stones and 20 healthy controls. Plasma and liver analyses were carried out using a well-tried HPLC technique that affords an accurate quantification of retinol, tocopherol, alpha- and beta-carotene, cryptoxanthin, and lycopene. Results: Plasma concentration of retinol, tocopherol, beta-carotene, and lycopene was significantly decreased in both patient groups, particularly in those with chronic hepatitis. In contrast, liver concentration of both esterified and free retinol, tocopherol, and some carotenoids was better preserved in the hepatitis group than in the cholelithiasis group. A strict correspondence between aminotransferases and the amount of liver-stored retinol was documented. Conclusions: Plasma vitamin and carotenoid depletion co-existing with preserved liver storage may indicate a functional defect in liver pool mobilization or even a real depletion of the antioxidant defenses, which play a key role in averting cellular damage. The implications for nutrition and therapy need to be taken into account.

Journal Article↗
PubMed1999

Low-dose aspirin treatment improves ovarian responsiveness, uterine and ovarian blood flow velocity, implantation, and pregnancy rates in patients undergoing in vitro fertilization: a prospective, randomized, double-blind placebo-controlled assay.

OBJECTIVE: To determine the effects of low-dose aspirin on ovarian response, uterine and ovarian blood flow velocity, and implantation and pregnancy rates in patients undergoing IVF. DESIGN: Prospective, randomized, double-blind placebo-controlled assay. SETTING: Department of Reproductive Medicine, CER Medical Institute, Buenos Aires, Argentina. PATIENT(S): Two hundred ninety-eight infertile patients (mean [+/- SDI age, 35.6+/-4.09 years) undergoing IVF cycles. INTERVENTION(S): In the treatment group, 149 patients underwent controlled ovarian hyperstimulation and received a daily dose of 100 mg of aspirin. In the control group, 149 patients underwent controlled ovarian hyperstimulation in association with placebo. MAIN OUTCOME MEASURE(S): Number of follicles, number of oocytes retrieved, serum E2 levels, uterine and ovarian pulsatility index, cancellation rate, number of embryos transferred, and implantation and pregnancy rates. RESULT(S): There were statistically significant differences between the treatment group and the control group, respectively, in the number of follicles (19.8+/-7.2 versus 10.2+/-5.3), number of oocytes retrieved (16.2+/-6.7 versus 8.6+/-4.6), serum E2 levels (2,923.8+/-1,023.4 versus 1,614.3+/-791.7 pg/mL), uterine pulsatility index (1.22+/-0.34 versus 1.96+/-0.58), ovarian pulsatility index (1.18+/-0.31 versus 1.99+/-0.56), pregnancy rate (45% versus 28%), and implantation rate (17.8% versus 9.2%). CONCLUSION(S): Low-dose aspirin treatment significantly improves ovarian responsiveness, uterine and ovarian blood flow velocity, and implantation and pregnancy rates in IVF patients.

Adult↗
PubMed1998

Pregnancy after human donor oocyte cryopreservation and thawing in association with intracytoplasmic sperm injection in a patient with ovarian failure.

OBJECTIVE: To describe a pregnancy after human donor oocyte cryopreservation in association with intracytoplasmic sperm injection in a patient with ovarian failure. SETTING: Department of Reproductive Medicine, CER Medical Institute, Buenos Aires, Argentina. PATIENT: A 48-year-old patient with ovarian failure. RESULTS: Ten donated oocytes were cryopreserved. Survival after thawing was 30%. Three oocytes were microinjected, and two embryos were obtained. The fertilization rate was 66%, and embryo development was 100%. Both embryos were transferred to a patient who had received hormonal replacement therapy. The attempt was successful, and a pregnancy was achieved after the transfer. CONCLUSION: In association with intracytoplasmic sperm injection, an adequate technique of freezing and thawing of human oocytes might achieve encouraging results in ART programs.

Adult↗
PubMed1998

Fitting the distributions of length of stay by parametric models.

OBJECTIVES: The purpose of this study was to assess the adequacy of three widely used models--Lognormal, Weibull, and Gamma--for describing the distribution of length of stay. This is a fundamental step in the development of outliers resistant (robust) methods for the statistical analysis of this kind of data, where the main objective is to determine measures of average and total resource consumption of groups of patients. Current practice uses several types of trimming rules, many of which are based on the Lognormal model, although theoretical and experimental bases are still insufficient. METHODS: The three models were adjusted using robust procedures based on M-estimators to approximately 5 million stays grouped by Diagnosis-Related Groups (DRGs). The resulting 3,279 samples were collected in five European countries during 3 years. RESULTS: Most of the distributions observed could be fitted with one of these models. The descriptions provided by the Gamma and the Weibull models were similar, and the Gamma model could be omitted. The casemix description provided by the Log-normal-Weibull family was, for certain countries, significantly better than the one provided by the single Lognormal model. Often, for a given DRG and a given country, length of stay distributions could be described with the same model during several years. A given DRG, however, usually had to be described by means of different models for different countries. CONCLUSIONS: Practical and conceptual consequences of the results are discussed. They can be extended to the analyses of other consumption variables used in health services. Statistical procedures for casemix description, including current rules of trimming, should be improved by means of more flexible families of models.

Belgium↗
PubMed1998

Age at death and rectangularisation of the survival curve: trends in Switzerland, 1969-1994.

OBJECTIVE: To check if signs of rectangularisation of the survival curve appeared during recent decades in Switzerland--that is, if life expectancy is approaching a maximum with a clustering of age at death around an average value (the so called "compression of mortality"). METHODS: Descriptive analysis of age of death and its trends over 26 years, as characterised by the modal value, median, and various percentiles beyond the median. POPULATION: All deaths occurring after the 50th birthday in Switzerland between 1969 and 1994 (n = 1,390,362). MAIN RESULTS: Age at death is increasing at a sustained rate at all percentiles equal or greater than 50, without any slow down in the trend during this period. The increase is more marked among women. Rates of increase are diminishing as the percentiles of age at death are higher, suggesting some clustering of deaths beyond the median value. However, the maximum age at death, if any, seems to be far from the current median values, even for women who enjoy a relatively high median age at death.

Age Factors↗
PubMed1996

Synthesis and biological evaluation of new fragments from kirromycin antibiotic.

New N-acyl derivatives of 1-N-desmethyl goldinamine were obtained from degradation of kirromycin. Periodate-oxidation of these derivatives provided new aldehydic fragments that were further elaborated. Both N-phenyl ureido and N-phthalimido derivatives of 1-N-desmethyl goldinamine are able to inhibit bacterial protein synthesis in cell-free assay and are active against whole microorganisms, although with lower potency than kirromycin. The derivatives from the aldehydic fragments are totally inactive.

Anti-Bacterial Agents↗
PubMed1993

Exploring models for the length of stay distribution.

Diagnosis Related Groups (DRG) are frequently used to standardize the comparison of consumption variables, such as length of stay (LOS). In order to be reliable, this comparison must control for the presence of outliers, i.e. values far removed from the pattern set by the majority of the data. Indeed, outliers can distort the usual statistical summaries, such as means and variances. A common practice is to trim LOS values according to various empirical rules, but there is little theoretical support for choosing between alternative procedures. This pilot study explores the possibility of describing LOS distributions with parametric models which provide the necessary framework for the use of robust methods.

Adolescent↗
PubMed1992

The circadian rhythm of the perinatal mortality rate in Switzerland.

The authors examine the relation between the perinatal mortality rate (PMR), birth weight in four categories, and hour of birth throughout the week in Switzerland, using data on 672,013 births and 5,764 perinatal deaths recorded between 1979 and 1987. From Monday to Friday, the PMR follows a circadian rhythm with a regular increase from early morning to evening, with a peak for babies born between 7 and 8 p.m. This pattern of variation has two main components: The circadian rhythms for the proportion of births in the four weight categories and the PMR circadian rhythm for babies weighing more than 2.5 kg. According to a cosinor model, which describes about 40% of the total variation in the PMR, the most important determinants are changes in the proportions of births: Low birth weight increases toward the afternoon and night. Mechanisms underlying the weight-specific timing of birth are discussed, including time selection of birth according to obstetric risks, the direct effect of neonatal and obstetric care, and chronobiologic behavior.

Birth Weight↗
PubMed1992

Evaluation of the consistency of Acute Physiology and Chronic Health Evaluation (APACHE II) scoring in a surgical intensive care unit.

OBJECTIVES: To determine the applicability of the Acute Physiology and Chronic Health Evaluation (APACHE II) scoring system in a Swiss ICU, and to evaluate its utility in evaluating data from 2 yrs of consecutive admissions to show that the predictability of outcome is similar to that predictability observed by Knaus et al. in 1985 (in 5,815 patients), with the provision that large numbers of patients are studied. DESIGN: Prospective clinical trial over 2 yrs, with statistical analysis of the Swiss patients, and between the Swiss patients and the patients studied by Knaus et al. Receiver operating characteristic curves were calculated. SETTING: Surgical ICU in a Swiss university hospital. PATIENTS: A total of 2,061 consecutive patients admitted to the surgical ICU who were classified as postoperative (elective or emergency) and nonoperative. Hospital mortality rate was considered. RESULTS: Patients were 53 +/- 16 yrs of age. Mean APACHE II score was 10.5 +/- 7.0. The mean APACHE II score was significantly (p < .001) lower in the 1,813 survivors (9.0 +/- 5.2) than in the 248 nonsurvivors (21.5 +/- 8.5). The mortality rate was higher among the Swiss patients when compared with the patients studied by Knaus et al. who had postoperative scores of 20 to 29 and nonoperative scores of > 24. The distribution of the scores and mortality rates were stable during the two study periods, as were the differences in mortality rates between the Swiss population and that population studied by Knaus et al. Sensitivity and specificity of the scores were highest in the emergency surgery group (87% and 78%), and lowest in the elective surgery group (76% and 73%). The APACHE equation underestimated the risk of death. CONCLUSIONS: The APACHE II score, because of its consistency over time and the stability of the mortality rates, can be used in our surgical ICU without modification. The calculated risk of death gives no additional information.

Adolescent↗
PubMed1991

Evaluation of arterial compliance-pressure curves. Effect of antihypertensive drugs.

A new high-precision ultrasonic device was developed to determine noninvasively arterial compliance as a function of blood pressure. Because of the nonlinear elastic properties of arterial walls, measurements of compliance can be appropriately compared only if obtained over a range of pressures. This apparatus was used to evaluate in a double-blind, parallel fashion the effect of three different antihypertensive drugs and of a placebo on radial artery compliance. Thirty-two normotensive volunteers were randomly allocated to an 8-day, once-a-day oral treatment with either a placebo, 100 mg atenolol, 20 mg nitrendipine, or 20 mg lisinopril. Blood pressure, heart rate, radial artery diameter, and arterial compliance were measured immediately before as well as 6 hours after dosing on the first and last days of the study. On the eighth day of administration, within 6 hours after dosing, lisinopril induced an acute increase in radial artery diameter, from 2.99 +/- 0.06 to 3.28 +/- 0.09 mm (mean +/- SEM, p less than 0.01). The compliance-pressure curve was shifted upward on day 1 (p less than 0.01) as well as on day 8 (p less than 0.05). None of the other drugs induced any significant modification of these parameters. Arterial compliance has a strong nonlinear dependency on intra-arterial pressure and therefore has to be defined as a function of pressure. Antihypertensive drugs acting by different mechanisms may have different effects on the mechanical properties of large arteries.

Adrenergic beta-Antagonists↗
PubMed1989

A meta-analysis of acupuncture for chronic pain.

Results of 14 randomized controlled trials of acupuncture for chronic pain were pooled in a meta-analysis and analysed in three subgroups according to site of pain; and in two subgroups each according to type to trial, type of treatment, type of control, 'blindness' of participating agents, trial size, and type of journal in which results were published. While few individual trials had statistically significant results, pooled results of many subgroups attained statistical significance in favour of acupuncture. Various potential sources of bias, including problems with blindness, precluded a conclusive finding although most results apparently favoured acupuncture.

Acupuncture Analgesia↗
PubMed1988

Robust regression in biological assay: application to the evaluation of alternative experimental techniques.

Robust Huber type regression and testing of linear hypotheses are adapted to statistical analysis of parallel line and slope ratio assays. They are applied in the evaluation of results of several experiments carried out in order to compare and validate alternatives to animal experimentation based on embryo and cell cultures. Computational procedures necessary for the application of robust methods of analysis used the conversational statistical package ROBSYS. Special commands for the analysis of parallel line and slope ratio assays have been added to ROBSYS.

Animal Testing Alternatives↗
PubMed1987

[Various abuses of statistics in medical research].

Statistics has become an indispensable tool in biomedical research. Thanks, in particular, to computer science, the researcher has easy access to elementary "classical" procedures. These are often of a "confirmatory" nature: their aim is to test hypotheses (for example the efficacy of a treatment) prior to experimentation. However, doctors often use them in situations more complex than foreseen, to discover interesting data structures and formulate hypotheses. This inverse process may lead to misuse which increases the number of "statistically proven" results in medical publications. The help of a professional statistician thus becomes necessary. Moreover, good, simple "exploratory" techniques are now available. In addition, medical data contain quite a high percentage of outliers (data that deviate from the majority). With classical methods it is often very difficult (even for a statistician!) to detect them and the reliability of results becomes questionable. New, reliable ("robust") procedures have been the subject of research for the past two decades. Their practical introduction is one of the activities of the Statistics and Data Processing Department of the University of Social and Preventive Medicine, Lausanne.

Humans↗
PubMed1987

Changes in the vascular reactivity of the isolated tail arteries of spontaneous and renovascular hypertensive rats to endogenous and exogenous noradrenaline.

We have investigated the changes in the responses to noradrenaline of isolated tail arteries of spontaneously hypertensive (SHR) and renovascular hypertensive rats (Wistar-Kyoto: two-kidney, one-clip model, WKY:2K1C) compared with normotensive (Wistar-Kyoto, WKY) rats. Renovascular hypertension was induced by 4 weeks' unilateral renal artery clipping. Arteries were vasoconstricted with exogenous noradrenaline, electrical field stimulation or high potassium. The effects of the latter two stimuli were abolished by reserpine and so were presumably dependent on the presence of endogenous noradrenaline. In the SHR the maximal vasoconstriction produced by all three stimuli was greater than in WKY. Dose-response curves were steeper and there was no change in threshold. Vascular mass was greater. We interpret these results as showing an increase in vascular reactivity in the SHR caused by structural adaptation. The WKY:2K1C responses to noradrenaline could also be explained in terms of structural adaptation but there was no increase in vascular mass. Sensitivity to potassium and electrical stimulation was decreased, suggesting a defect in vascular neurotransmission. This was supported by the observations of a decreased arterial noradrenaline content and of decreased sensitivity to cocaine.

Animals↗
PubMed1985

[Effect of eating habits on morbidity in 645 patients at a specialized clinic].

Among 645 obese patients examined at an out-patient clinic for obese patients by physical examination and a computerized questionnaire, two subgroups of patients could be identified according to their nutritional preferences: 177 patients preferred carbohydrates exclusively (group A) and 73 patients fat exclusively (group B). No definite preferences were formulated by the other patients. Among patients under 25 years, only 3 belonged to group B and 49 to group A, while in older patients no significant differences were found. Among patients with BMI less than 30, there were significantly fewer patients from group B than from group A (p = 0.006), while in patients with BMI greater than 30 no significant difference was observed. There were significantly more men in group B than in group A. 57% of the patients of group B complained of physical symptoms related to their obesity, compared to 37% in group A (p = 0.006). 26% of group B suffered from joints and muscles compared to 13% of group A (p = 0.003). Hyperglycemia (greater than 5,6 mmol/l) was found in 21% of group A and in 40% of group B (p less than 0.005). Hypercholesterolemia (greater than 6.5 mmol/l) was found in 20% of group A and in 32% of group B (p less than 0.05). In conclusion, obese patients who prefer fat have more general symptoms related to obesity, more abnormal physical signs, and more frequently have hyperglycemia and hypercholesterolemia than patients who prefer carbohydrates.

Adolescent↗